Tag Archives: bmw e30 polyurethane bushing kit

Today were going to talk about poly and Delrin differential bushings for your E30, your, E36ti’s, yours Z3’s. They all compatible.

They all take the same some the sub-frame bushings. They all take the same sub-frames pretty much, theoretically speaking, and the same diff bushing. Today here we got all of our diff bushings that we offer. It’s a Delrin version, which is basically for all-out race guys. It’s good for track application, if you really don’t want that diff to move, Delrin the one for you. It will transmit a little bit more noise, being that it is solid plastic basically.

Then you got your 80-Series, which is the softest poly available. It’s a happy street-friendly durometer hardness. It doesn’t transmit as much noise obviously as the Delrin, being that it will absorb a lot of the noise. It’s really good for autocross, occasional track days, it’s just an all around good bushing. Then you got your 95 which is the hardest poly available. This is the one that we like, it’s the happy medium. It will transmit a ton, a little bit more noise than the 80 but not quite as much as the Delrin. They all basically have the same geometry, they’re solid bushing. As you can see, there is no holes like the factory bushing. The factory bushing have only is connected two or three points, and it was made for comfort, it was design for comfort. Even when you’re going with the softest poly it’s going to be a great upgrade over your stock bushing because it’s attached physically in more area.

They all have a lifetime warranty,all made in USA, here in Westminster California. It’s meant to replace part number 331 71 135242 and that basically is found in E30s, Z3s and E36ti’s, even your 325iIX’s take the same differential bushing, so it’s also compatible with that. Now this will … it’s something that will add responsiveness, it’s going to limit differential movement. A failed if bushing basically sounds like an ape trying to escape from your trunk. There’s usually thump, there’s things going on in the trunk. Usually when you put it in gear, stuff like that, you’re going to hear a bang thump something. Monkey’s trying to get out, usually it’s a because the differential bushing is gone, it’s literally not connected anymore. Installation is simple you will need a press because it does get pressed into your factory differential cover. It’s compatible with M Coupe covers, so even if you’re running on your E30 the upgraded differential cover from the M Coupe or even your E36 or 318ti E36 unit, they’ll accept the M Coupe cover, this will fit it. It’s a great upgrade, very low-cost. It’s a maintenance thing. These things are are quite old now and it’s usually time to replace them. Now this is kind of a while you’re at it thing. If you guys who put in LS1’s, the M60’s, S54 the big motors putting in a little more power. While you look at your differential it’s probably a good idea to look at our secondary diff mount.

This is one of the piece of the components, but basically what this does is it adds a second ear to your differential. Basically this came in later 36’s and stuff like that. BMW basically realized that they should have two years on the differentials. E30s obviously didn’t, they had one ear. This is a great upgrade, very low budget compared to the damage that could occur to your differential. It obviously will require another differential bushing and it will also accept a stock differential bushing. That’s also a good upgrade. Hopefully this made your understanding of E30 diff bushings a little bit better. These Garagistic Poly/Delrin E30, z3 318ti diff bushings are made right here in the USA and come with a lifetime warranty.

You can also check out on our app and our website. If you have any questions, please feel free to drop us a line or visit us at our website.

All parts can be found on the Garagistic app (ANDROID OR APPLE) or on our website www.garagistic.com and if you have any questions, please feel free to shoot us an email or give us a call. We’d be happy to help.

The time has come, you have finally decided to reinforce your E30 front subframe; it’s not as hard as you might think!
Our friends at Salt City Euro’s show you how to get it done with the Garagistic reinforced E30 subframe!
This is one of the most important modifications you should make if you’re driving your car hard or adding more power. The Garagistic reinforced subframe arrives freshly powder coated and includes welded tabs that make the sway bar and engine mounts much stronger. This is necessary to prevent breaking the subframe. This is a stock subframe that was used with a S50 motor. You can purchase a reinforced subframe over at the Garagistic website.

There are multiple ways to complete this job, which will also depend on the configuration of your car. For example, we have no power steering, but we do have a 24 valve oil pan which prevents us from removing the steering rack on the car, as you could on an E30 with an M20 or M42. We won’t mention the power steering system again. You are on your own with that. Use this as a general guide.

We’re using an engine support bar to suspend the engine properly since we’ll be removing everything that is holding the engine in place. To complete this job you will need the following tools: the jack and jack stands, an engine support bar, a wrench with 13, 16, 17, and 19 mm sockets, and a ball joint removal tool. We also needed a small pry bar. Start by loosening your lug bolts and securing the car on jack stands. We then removed the wheels and loosened the control arm and tie rod end bolts. You’ll need a 19mm socket for the control arm and a 17mm socket for the steering rack tie rod ends. We’re using a basic ball joint tool to remove the ball joints. Before attempting to remove the ball joints, make sure you leave the nut flush with the threads of the ball joint. This will give you a larger surface to work with and protect your threads. Don’t be afraid to apply a lot of pressure, it takes quite a bit to pop those ball joints out.

Next, remove the two 17mm bolts holding the control arm bushings in place. You may have to carefully pry them off the car’s chassis. Remove the lower nuts holding the motor mounts in place. Disconnect your steering shaft from the steering rack. We are showing this on another car so you can clearly see it. Normally the engine would block the view. At this point you can carefully raise your engine to take all the weight off the motor mounts. We also used the jack with a 2×4 for extra safety. Once you’ve loosened and removed the four 17mm bolts holding the subframe in place, carefully lower the subframe. At this point it is time to disassemble your subframe assembly. Remove the steering rack, sway bar, and control arms, then transfer the steering rack to your new subframe.

It’s time to reinstall the e30 subframe on your car. This is much easier with the help of a friend. Align and reinstall your control arms. A small tip: if the ball joint is spinning and does not want to tighten, you can use a jack to press the joint into the knuckle. Reinstall your sway bar and tighten to spec. Finally, remember to tighten and torque your motor mounts to spec.
Congratulations.

You’ve successfully swapped the subframe on your E30. This job is time consuming and may require two people at times. We estimate that it takes 2 to 4 hours to complete depending on skill.

On a scale of 1 to 10, we’d give this job a 5, with 1 being a wheel change and 10 being a full top to bottom engine rebuild.

All Garagistic E30 Front Subframe reinforcements are made in house here in the USA.

Orange, Yellow Purple – Is there a difference? Which one is harder? What does the color mean? But I’m just looking for a slightly sportier feel. Is Urethane the same as Polyurethane? All of these questions, and more, will be answered.

What does it all mean?

I’ll save you the suspense – Urethane IS Polyurethane, just in a different form. And color means nothing in terms of performance. Some suppliers use a signature color to represent their company. Some companies don’t care what color is used. And some companies use colors to differentiate batches due to a slightly altered methodology of production or in other terms, a ‘date code’ identifier.

Yes, 95A is indeed harder than 80a and will give a sportier feel in the application of suspension and drivetrains. More on that later. But because 95A is harder than 80A, it is much more easily machineable (turning, facing, drilling, boring…etc). But why is it actually harder or softer? For all intents and purposes, Urethane is the same as Polyurethane. Urethane is the monomer (ethyl carbamate). Basically, polyurethane is a long chain of urethane molecules, and they are bonded front to back, front to back, and so on….

The answer at a high level is: Isocyanates*, Polyols, and Crosslinking. Flexibility is attributed to the polyol, which is a soft, elastic polymer and its reaction with the Isocyanates (averaging 2 or more groups per molecule).

The theory is that high amounts of crosslinking within short chains combined with lower molecular weight polyols give tough or rigid polymers. Conversely, long chains, low crosslinking, and a higher molecular weight polyol give a polymer that is very stretchy.

Polyurethane crosslinking allows the polymer to be a three-dimensional network. As a result, the overall molecular weight is very high and allows polyurethanes the property of not softening up when heated, aka ‘thermosetting polymers’.

Polyurethane was invented during the WWII era by the German Professor, Dr. Otto Bayer (1902-1982), known as the “father” of the poly industry. From there, polyurethanes can be found in adhesives, coatings, foams and finally flexible foams in the late 50’s. Today, you can see polyurethanes in virtually anything, including structural moldings for anything you see. Footwear, appliance, home, garage…etc. This is all great, but here we’re going to discuss how polyurethanes have shaped our automotive aftermarket culture for use specifically in swapped BMW’s.

Durometer (more commonly known as ‘Shore’) is nothing more than a measure of hardness. And within that, there are several different scales. Most common is the ASTM D2240 Type A for polyurethanes. Hence the “A” at the end of the number. (examples: 70A, 80A, 95A). Scale is from 0 to 100. The higher the number, the harder the polyurethane. A calibrated instrument is used to provide a very specific force to a poly of certain dimensions, creating an indentation in the material. The machine holds its indented force in the poly for 15 seconds, then is released. Immediately thereafter, the indentation is measured for depth. For shore “A”, a hardness range of 100-0 is proportional to the depth of (0.0” – 0.1”+). Aka, no indentation, the harder the material and therefore a durometer of 100 is assigned. Durometer is a dimensionless quantity. And because of that, there are many scales depending on the standard that’s used and the best scale is chosen based on the properties of the polyurethane. Here is a quick scale below of the durometer and the scale used for various materials. Again, most if not all automotive applications deal with shore, or scale “A”.

Now that you know about the history of polyurethane, how it works, and how it’s measured hardness works, how about common-day applications.

You don’t always need 95A all around or 80A all round on your e30. Sometimes it’s critical to have harder poly on some areas of your e30 while softer on others. Factory e30 rubber mounts for most applications, including oil filled motor mounts are in the 60A-65A range. That’s pretty soft, but to give you comparison compared to stock, see below.

60-65A – Stock e30

70A – 25% stiffer

80A – 30-35% stiffer

95A – 75-80% stiffer

While the 60A-65A bushings do result in a lot of engine movement, especially during hard acceleration, the benefit is a comfortable driving experience and less noise transmission through your e30.

For that perfect balance, I recommend Garagistic’s 80a e30 mounts.

Just a quick list of the benefits of Polyurethane bushings over stock e30 rubber.

It allows your e30s suspension to react quicker to changes in road conditions, quicker steering, more responsive and receptive to your inputs as the driver. As a result, the power lost in the soft bushings is actually going right to your wheels!!

Polyurethane is easy to install, no presses or special tools needed!

Polyurethane outlasts rubber bushings. In most applications, it will last the life of your daily road driven e30!

You can get custom offset fitment for race applications to help with wheel alignment, ride height…etc.

Want to go delrin on your e30? or even crazier and get solid bushings? Not a problem, only it is. If you daily drive your E30 and want to go delrin or solid, the ancillary setback is that the E30 chassis itself is not particularly designed for this type of vibration from the drivetrain and the roads. And because of that, things happen. Connectors dislodge, pins and electrical connections come loose, screws slowly back out and some bolts loosen up. For a car manufacturer to design to those strict requirements of solid mounted bushings, the car would look like a tank. You can use delrin or even a solid mounted configuration, but just beware of the long term consequences on your e30 due to daily driving around town.

What else does Garagistic offer?

Thanks for reading and stay tuned for more posts. At least 2 new posts per week, with one of them guaranteed to be dedicated to the ongoing E30-LS1 project!!

* Recent efforts are attempting to minimize the use of isocyanates to synthesize polyurethanes, because the isocyanates raise severe toxicity issues. Non-isocyanate based polyurethanes (NIPUs) are in the works as a new class of polyurethane to alleviate environmental concerns.